Module1

BIOMEDICAL INSTRUMENTATION - MODULE 1

Introduction to Biomedical Instrumentation

Human and Machine

• The human body is often referred to as the finest technology in the world, emphasizing its complexity and efficiency.

Human Body Anatomy

• Structure: The human body consists of several parts including:

  • Head

  • Neck

  • Torso

  • Two arms

  • Two legs

• Cellular Composition: Approximately 100 trillion cells form the entire body.

• Organ Systems: Major organ systems include:

  • Musculoskeletal System

  • Cardiovascular System

  • Digestive System

  • Endocrine System

  • Integumentary System

  • Urinary System

  • Lymphatic System

  • Immune System

  • Respiratory System

  • Nervous System

  • Reproductive System

• **Constituents in a Normal 60 kg Male: **

  • Oxygen: 38.8 kg (25.5% of atoms)

  • Carbon: 10.9 kg (9.5% of atoms)

  • Hydrogen: 6.0 kg (6.3% of atoms)

  • Nitrogen: 1.9 kg (1.4% of atoms)

  • Calcium: 1.2 kg (0.2% of atoms)

  • Phosphorus: 0.6 kg (0.2% of atoms)

  • Potassium: 0.2 kg (0.07% of atoms)

Cardiovascular System

Overview

• Components: Heart, veins, arteries, capillaries.

• Function: Circulation of blood; transport of oxygen and essential minerals to organs.

Heart Structure

• Divided into:

  • Left Side: Pumps blood throughout the body.

  • Right Side: Pumps blood to lungs for oxygenation.

• Three layers of the heart:

  • Endocardium: Inner layer providing smooth surface.

  • Myocardium: Middle layer made of muscle fibers, responsible for contractions.

  • Epicardium (Pericardium): Outer layer that prevents friction.

Heart Valves

• Tricuspid Valve: Prevents backflow from right ventricle to right atrium.

• Bicuspid (Mitral) Valve: Prevents backflow from left ventricle to left atrium.

• Pulmonary Valve: Prevents backflow to the right ventricle.

• Aortic Valve: Prevents backflow to the left ventricle from aorta.

Blood Transport Mechanism

• Types of Blood Vessels:

  • Arteries: Thick-walled vessels carrying oxygenated blood away from the heart.

  • Veins: Thin-walled vessels carrying deoxygenated blood back to the heart.

  • Capillaries: Smallest vessels facilitating nutrient, oxygen, and gas exchange at the cellular level.

• Circulation Types:

  • Pulmonary Circulation: Deoxygenated blood flows from right ventricle to lungs and back to left atrium.

  • Systematic Circulation: Oxygenated blood is pumped from left ventricle through the aorta to the body.

The Physiology of Respiration

Importance of Breathing

• Provides oxygen, necessary for energy production in cells.

• Without oxygen, cells cannot produce energy, leading to cell death.

Key Concept: Perfusion

• Definition: The supply of blood and oxygen to cells and tissues.

• Impact: Without perfusion, cells die.

Energy Production in Cells

• Mitochondria: Primary site for ATP (Adenosine Triphosphate) production.

• Process:

  • Oxygen consumed,

  • Carbon dioxide produced as a waste product,

  • Glucose as fuel.

Gas Exchange Mechanism

• Oxygen from air diffuses into blood in the lungs, transported to cells.

• Carbon dioxide from cells diffuses into blood, expelled during breathing.

Respiratory System Anatomy

Structure

• Composed of tubes that transfer air to the alveoli where gas exchange occurs.

• Alveoli: Microscopic air sacs surrounded by capillaries, site of gas exchange (O2 and CO2).

Gas Exchange Process

• Occurs via diffusion in alveoli:

  • O2 moves from alveoli to capillaries,

  • CO2 moves from capillaries to alveoli for exhalation.

Ventilation: Breathing Mechanics

Breathing Process

• Inspiration:

  • Ribs rise, diaphragm lowers, lung volume increases, and pressure decreases.

  • Air enters the lungs.

• Expiration:

  • Ribs fall, diaphragm domes, lung volume decreases, and pressure increases.

  • Air exits the lungs.

Control of Ventilation

• Increased physical activity raises demand for oxygen, modifying breathing rate and depth.

• Chemoreceptors detect CO2 levels in the blood and signal the respiratory centers to adjust breathing.

Physiology of the Nervous System

Central Nervous System (CNS)

• Comprised of the brain and spinal cord.

Spinal Cord Function

• Sensory and motor innervation, two way conduction pathway, major reflex center.

Anatomical Classification of the Brain

• Key parts include:

  • Cerebral Hemispheres

  • Diencephalon (Thalamus and Hypothalamus)

  • Brain Stem (Midbrain, Pons, Medulla)

  • Cerebellum

Lobes of the Brain

• Frontal, Parietal, Temporal, Occipital lobes, and Insula.

Prefrontal Cortex Functions

• Associated with cognition, social skills, impulse control, and complex reasoning.

Neurons and Synapses

Types of Neurons

• Sensory Neurons: Relay information from sensory organs.

• Motor Neurons: Transmit commands from brain to muscles.

• Interneurons: Connect neurons within CNS.

Structure of a Neuron

• Dendrites: Receive information.

• Cell Body: Contains nucleus and metabolic apparatus.

• Axon: Conducts impulses away from cell body.

Communication Between Neurons

• Action potentials trigger neurotransmitter release, influencing adjacent neurons.

Summary of Action Potentials

Definition

• Action potentials are rapid electrical signals allowing communication along neurons.

Mechanism

• Upon reaching threshold, Na+ channels open, resulting in depolarization followed by K+ efflux that leads to repolarization.

Refractory Periods

• Absolute Refractory Period: No new action potential can be initiated.

• Relative Refractory Period: Initiation of an action potential requires a stronger stimulus.

Conduction Types

• Continuous Conduction: In unmyelinated axons, action potentials propagate along adjacent patches of membrane.

• Saltatory Conduction: In myelinated axons, action potentials jump from node to node, increasing transmission speed.

End of Module - 1

Conclusion

• This module provides foundational knowledge on human anatomy, physiology of the cardiovascular and respiratory systems, and neuronal communication, integral to the understanding of biomedical instrumentation.